Going to Oregon this October for a rifle mule deer hunt on the western side of Umatilla National Forrest. Was wondering if anybody has been close that could help out with what kind of weather to expect and preferred caliber for the mulies.

I have not hunted in Oregon but have hunted for muledeer in the north west and I would say a 270 is a good caliber and I would figure the weather could be anything from cold, rain, snow or warm and sunny.
Bring clothing for almost any condition and watch the weather forecast right up till the time you leave.

Never hunted Oregon, but I shot my Mulie with a .270 at 250 yrds. You can use any of the stouter whitetail calibers, but you need to know its (and your's) limitations. That being said, there's usually plenty of opportunities to shoot far when hunting Mulies. I think if I did it again I'd take my 7mm Rem Mag.

I agree with what Dusty said about clothes. Its better to take too much than not enough!

I concur on the 270. Haven't hunted Oregon but I have killed several big Mule Deer bucks with my 270 shooting 130 grain Fed Premium. Plenty of bullet to kill them but very flat shooting for shots out to 400 yards. If you sight in for 2 inches high @ 100 yards you can hold on target out to 250 yards.

I tried hunting mule deer in Oregon once about 20 years ago near Bend on public land. I've hunted public land in most of the Western States and found that the farther back I go, the fewer people I see and the more animals there are. I look at the maps to find the most remote place I can where there are no roads. I found just the place on that hunt, but was still over run with other hunters. At times it was like being out pheasant hunting. Wave after wave of groups of people walking around, talking and making a racket all day long. I tried to use them to flush out the deer, but after glassing for several days, realized that there just wasn't very many deer there. I had another tag in Northern CA that was for a Wilderness area, so I left Oregon early and backpacked into a very remote spot, set up camp and scouted the area for three days. Third day of the season I shot a nice buck and packed him out the next day. I never saw another human for 6 full days, which is my person record!!!!

If you go to Oregon, remember that deer season is a huge event there and there isn't a lot of public land. If you have private land to hunt on, you should do fine. Otherwise, it's going to be about getting where all the other hunters are not at, and finding an area that holds animals.

Eddie